JPS60107874A - Light emitting element - Google Patents

Abstract

PURPOSE:To improve the photocoupling efficiency with an optical fiber while making it feasible to form a semi-spherical lens with specific shape at all times by a method wherein a lens type adhesive resin is formed on a photo-leading surface with step difference higher than the surface of a peripheral electrode directly above a light emitting part. CONSTITUTION:A lens type photoresist layer 21 depending upon refractive index of a transparent adhesive resin is formed directly above a light emitting part 7 to produce a photo-leading surface 8. Next an electrode 61 is formed on the surface of a substrate forming a step difference while an electrode material and the photoresist are removed and then the resin is softened on the surface 8 to form the lens type transparent adhesive resin with the effect of semi-spherical lens. Through these procedures, the lens 21 with specific shape depending upon the surface tension of the resin may be formed by means of turning the reversed light emitting element so far produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a light emitting device, and more particularly to a light emitting device that allows light from a light emitting portion to enter an optical fiber efficiently.

Background of the Technology For example, a light emitting element as shown in FIG. 1 α*be', whose cross-sectional outline is shown, is used as a light emitting element that efficiently allows light from a light emitting diode to enter an original fiber. Figure 1 α
is a light-emitting element in which a ball lens 4 is adhesively mounted on a light extraction surface B with an adhesive 5 in order to efficiently input light from a light-emitting portion 7 of a light-emitting diode 2 into an optical fiber 1.

61 and 62 indicate electrodes. FIG. 16 shows a hemispherical lens 41 instead of the spherical lens 4 in the light emitting device of FIG. 1 α.
This is a light emitting device that is adhesively loaded. Further, FIG. 1C shows a light emitting element in which a hemispherical lens 40 is formed on the light emitting diode 2 itself by etching, for example, instead of the spherical lens or hemispherical lens in FIGS. 1α and 1b.

Prior Art and Problems The conventional light-emitting elements illustrated in Figures α and b all require different types of glass lenses, making them economically expensive. This has the disadvantage that the focal length of the light changes, resulting in variations in the optical coupling efficiency with the optical fiber. In the conventional light emitting device shown in FIG. 1C, a hemispherical lens is formed by etching the light emitting diode itself, which requires a special technique such as ion beam etching, making it difficult to control and economical. The price will be high.

OBJECTS OF THE INVENTION It is an object of the present invention to overcome the conventional drawbacks and provide a highly productive light emitting device with high optical coupling efficiency with an optical fiber. The figures will be explained in detail below.

Embodiment of the Invention FIG. 2 shows a schematic cross-sectional configuration of an embodiment of the light emitting device of the invention. The same reference numerals as in FIG. 1C indicate the same parts. 21.2
Reference numeral 2 denotes a hemispherical light-condensing lens and an excess adhesive resin portion made of a light-transmitting adhesive resin, such as an epoxy optical adhesive, which is cured by heating or ultraviolet light. As shown in FIG. 2, the light emitting element of the present invention utilizes the viscosity of a translucent adhesive resin to form a lens shape 42 of the adhesive resin. Next, an embodiment of the manufacturing process for concretely realizing the light emitting device of the present invention will be described with reference to FIGS. 3a to 3f.

Immediately above the light emitting part 7 of the base 10 of the light emitting element (2. Accurately correspond to the position of the light extraction surface, using normal photoetching technique) 2. The necessary lens shape determined by the refractive index of the translucent adhesive resin. A photoresist layer 11 is formed (Fig. 6 α).
). This portion corresponds to the light extraction surface. In this example, the translucent adhesive resin is an epoxy optical adhesive, with a refractive index of 1.5 to 1.8 and a hemispherical lens shape of 100 to 300.
It is μmφ. Next, chemical etching, such as G
a H3P0° system for A J system, HCl for InP system
Depending on the system, a step of about 50 μm is formed (Fig. 6b).

Vapor deposition, sputtering, etc. on the surface of the base 10 on which the steps are formed,
For example, electrode materials such as AuGmNi can be prepared by vacuum evaporation.
Then, electrodes 61 and 65 are formed (FIG. 3C). Next, the electrode material (electrode made of AtbGeNi) 66 and the photoresist 11 on the light extraction surface 8 are removed by, for example, a lithophotographic method (FIG. 3d). Next, the light extraction surface 8
An epoxy-based optical adhesive, which is a translucent adhesive resin, is dropped on top and softened by heating or ultraviolet rays to form a lenticular translucent adhesive resin 21' exhibiting the effect of a hemispherical lens (see Fig. 3).
). In this example, the light-emitting element obtained in the process shown in Fig. 6 was turned over and hardened in a constant temperature bath at 150°C for 1 hour (2). When the bottom part is sucked by the vacuum collet 23 and rotated as shown at 25, a lens 21 with a constant shape determined by the surface tension of the translucent adhesive resin is formed.24 indicates the direction of vacuuming. show.

Effects of the Invention As described above, according to the present invention, there is no need for a ball lens or a hemispherical lens as in conventional light emitting elements, and the manufacturing process is shortened and the cost becomes low. Furthermore, there is no need for special processing methods such as a built-in lens, which is one of the conventional methods. Furthermore, since a stepped light extraction surface is formed directly above the light emitting part by photoetching, the center of the hemispherical lens made of translucent adhesive resin can be set, and stable optical coupling efficiency to the optical fiber can be achieved. At the same time, the temperature of the transparent adhesive resin,
That is, by keeping the surface tension constant, a hemispherical lens having a constant shape can be formed at all times, which has the great advantage of improving manufacturing yield.

[Brief explanation of the drawing]

Figure 1 α, b, and a are schematic cross-sectional diagrams of the configuration of a conventional light emitting element;
FIG. 2 is a schematic cross-sectional view of the structure of the present invention, and FIGS. 3(a) to 3(f) are manufacturing process diagrams of the light emitting device of the present invention. 1... Optical fiber, 2... Light emitting diode, 3...
・Light, 4... Spherical lens, 41... Hemisphere lens, 5.
... Adhesive material, 61.62 ... Electrode, 7 ... Light emitting part,
8... Light extraction surface, 40... Hemispherical lens of the light emitting element itself, 21... Hemispherical lens of translucent adhesive resin,
22... Adhesive resin, 21'... Lens-shaped translucent adhesive resin, 26... Vacuum collet, 24... Vacuuming direction, 25... Rotation direction Patent applicant Sumitomo Electric Industries, Ltd. Agent Patent Attorney Co., Ltd. Tamamushiku Fifth Department Figure 1 α Figure 2 Figure 3

Claims (1)

[Claims] In a light emitting element having a condensing lens on a surface for extracting light from a light emitting part, the light extracting surface is located directly above the light emitting part with a step higher than the outer peripheral electrode surface, and a lens-shaped lens is provided on the light extracting surface. A light emitting element made of adhesive resin.